From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Seeking for papers about tagged types vs access to subprograms
Date: Thu, 16 May 2013 15:54:13 +0200
Date: 2013-05-16T15:54:13+02:00 [thread overview]
Message-ID: <lnx0yaymncw7$.pqorucpcq8r3$.dlg@40tude.net> (raw)
In-Reply-To: alpine.DEB.2.02.1305160829510.2501@whirlwind
On Thu, 16 May 2013 09:10:11 -0400, Peter C. Chapin wrote:
> On Thu, 16 May 2013, Dmitry A. Kazakov wrote:
>
>>>> So,
>>>>
>>>> X, Y : Driver;
>>>>
>>>> have same values?
>>>
>>> Yes, I would say so.
>>
>> Really? X is an *equivalent* of Y?
>
> Sure. If it were allowed the expression 'X = Y' should return True.
If X嚙踝蕭Y, you don't need two instances of.
> I realize that equivalence of functions is a difficult concept in general
There is nothing difficult in that. A function is a set of pairs. Two sets
are equal when contain same elements.
> X and Y above of course may contain different state information as they
> run but that's all related to the operation of execution; it doesn't
> distinguish their "task values."
Of course it does. For example: it can happen that X'Terminated /=
Y'Terminated.
>> Because the literal 2 [of type Integer] denotes the same value in all
>> contexts. But X, Y : Driver clearly do not do that. If X and Y are not
>> equivalent how they could have the same value?
>
> I guess this is where we disagree. To me X and Y do denote the same value
> in all contexts; they are equivalent.
They are evidently not, which can be easily demonstrated by presenting a
program which would yield different results depending on whether X or Y is
used.
>> Either the values are different or else you need to bring some other
>> stuff beyond types, values and operations into the picture.
>
> Are you referring to the execution state here?
It is your concept, I am only giving you enough rope to hang yourselves...
> To my mind that dynamic
> information is just part of the operation of execution. It's necessary to
> make that operation work but, yes, I agree that it is a separate matter
> from the types and values, etc.
Which means that your model is inadequate to describe the way programs
work, and more generally to programming.
>>>> e : constant :=
>>>> 2.71828_18284_59045_23536_02874_71352_66249_77572_47093_69996;
>>>
>>> As I understand it, 'e' has type Universal_Float and the 2.718... is a
>>> value inhabiting that type. I guess I don't understand what point you are
>>> making here.
>>
>> The point is about the value of e. You said that when declared as I did, it
>> has no significance, just a random pattern of bits. Do I interpret you
>> correctly? Does this same logic apply to e of Ada.Numerics? If not where is
>> a difference?
>
> We're talking about two different 'e's here. In the first case 'e' was an
> enumeration literal. The type in that example was suggestively named
> Transcendental_Constants (or something like that... I forget exactly), but
> any connection between 'e' and the mathematical value of e was purely in
> the mind of the programmer.
How Universal_Integer is different?
> In Ada terms 'e' was a value of that type but
> nothing beyond that. That's what I meant by it not having any
> significance.
>
> In the second case 'e' is a named number bound to a value in the
> Universal_Float type that is clearly intended to be the mathematical e...
How it is more "clearly intended" than enumeration 'e'?
Note that neither is mathematical e. They *model* e = as you said "purely
in the mind of the programmer." This is what value is, an idea behind a
computational state.
> at least to the closest degree permitted by the available values in that
> type (I guess in this case it's really limited by the amount of space the
> implementer wants to use when writing the declaration. Am I correct in
> saying that Universal_Float has infinite precision?)
It has an indefinite precision.
> I suppose I don't understand the point you were trying to make originally
> with the enumeration type. There 'e' was a value of the specified type.
> Was that it?
The value of e was meant to represent the transcendental number e. The type
was meant to model real numbers. Similarly Ada.Numerics e is meant to
represent e. And Universal_Real is meant to model real numbers. e is not
Ada term. It is a term of mathematical analysis. Neither type is real, they
are only models of.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2013-05-16 13:54 UTC|newest]
Thread overview: 202+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-28 5:14 Seeking for papers about tagged types vs access to subprograms Yannick Duchêne (Hibou57)
2013-04-30 0:31 ` Yannick Duchêne (Hibou57)
2013-04-30 0:41 ` Shark8
2013-04-30 1:00 ` Yannick Duchêne (Hibou57)
2013-05-02 1:18 ` Randy Brukardt
2013-05-02 2:29 ` Jeffrey Carter
2013-05-06 10:00 ` Yannick Duchêne (Hibou57)
2013-05-06 10:18 ` Dmitry A. Kazakov
2013-05-06 10:55 ` Yannick Duchêne (Hibou57)
2013-05-06 12:11 ` Dmitry A. Kazakov
2013-05-06 13:16 ` Yannick Duchêne (Hibou57)
2013-05-06 14:16 ` Dmitry A. Kazakov
2013-05-06 15:15 ` Yannick Duchêne (Hibou57)
2013-05-06 18:55 ` Dmitry A. Kazakov
2013-05-06 20:05 ` Adam Beneschan
2013-05-07 7:30 ` Dmitry A. Kazakov
2013-05-10 4:33 ` Yannick Duchêne (Hibou57)
2013-05-07 20:35 ` Jacob Sparre Andersen news
2013-05-07 20:44 ` Yannick Duchêne (Hibou57)
2013-05-07 22:32 ` Dennis Lee Bieber
2013-05-07 23:10 ` Adam Beneschan
2013-05-08 0:18 ` Shark8
2013-05-10 4:34 ` Yannick Duchêne (Hibou57)
2013-05-10 8:27 ` Simon Wright
2013-05-10 18:08 ` Niklas Holsti
2013-05-08 7:38 ` Dmitry A. Kazakov
2013-05-08 7:59 ` Yannick Duchêne (Hibou57)
2013-05-08 8:23 ` Dmitry A. Kazakov
2013-05-08 9:39 ` Yannick Duchêne (Hibou57)
2013-05-08 9:51 ` Yannick Duchêne (Hibou57)
2013-05-08 10:23 ` Dmitry A. Kazakov
2013-05-08 11:08 ` Yannick Duchêne (Hibou57)
2013-05-08 15:29 ` Dmitry A. Kazakov
2013-05-08 16:13 ` Yannick Duchêne (Hibou57)
2013-05-08 18:17 ` Dmitry A. Kazakov
2013-05-10 4:35 ` Yannick Duchêne (Hibou57)
2013-05-08 20:27 ` Randy Brukardt
2013-05-09 7:33 ` Dmitry A. Kazakov
2013-05-09 22:19 ` Randy Brukardt
2013-05-10 3:29 ` Yannick Duchêne (Hibou57)
2013-05-10 4:16 ` Yannick Duchêne (Hibou57)
2013-05-10 8:42 ` Dmitry A. Kazakov
2013-05-10 11:18 ` Yannick Duchêne (Hibou57)
2013-05-10 12:15 ` Dmitry A. Kazakov
2013-05-10 12:40 ` Yannick Duchêne (Hibou57)
2013-05-10 12:59 ` Yannick Duchêne (Hibou57)
2013-05-10 13:54 ` Dmitry A. Kazakov
2013-05-10 14:01 ` Yannick Duchêne (Hibou57)
2013-05-10 14:27 ` Dmitry A. Kazakov
2013-05-10 15:20 ` Yannick Duchêne (Hibou57)
2013-05-11 7:22 ` Georg Bauhaus
2013-05-10 18:04 ` Niklas Holsti
2013-05-10 19:33 ` Yannick Duchêne (Hibou57)
2013-05-11 0:18 ` Randy Brukardt
2013-05-11 7:14 ` Yannick Duchêne (Hibou57)
2013-05-11 21:06 ` Niklas Holsti
2013-05-11 23:19 ` Shark8
2013-05-12 6:09 ` Niklas Holsti
2013-05-14 2:02 ` Randy Brukardt
2013-05-12 6:44 ` Yannick Duchêne (Hibou57)
2013-05-12 8:10 ` Niklas Holsti
2013-05-12 8:49 ` Yannick Duchêne (Hibou57)
2013-05-12 18:56 ` Jeffrey Carter
2013-05-12 22:15 ` Robert A Duff
2013-05-13 0:26 ` Jeffrey Carter
2013-05-13 7:03 ` Yannick Duchêne (Hibou57)
2013-05-13 13:15 ` Robert A Duff
2013-05-13 17:30 ` Jeffrey Carter
2013-05-13 18:01 ` J-P. Rosen
2013-05-13 18:39 ` Bill Findlay
2013-05-13 18:57 ` Jeffrey Carter
2013-05-13 19:13 ` Robert A Duff
2013-05-13 20:38 ` J-P. Rosen
2013-05-14 7:26 ` Dmitry A. Kazakov
2013-05-14 20:00 ` Robert A Duff
2013-05-15 10:10 ` Dmitry A. Kazakov
2013-05-14 19:56 ` Robert A Duff
2013-05-15 4:24 ` Yannick Duchêne (Hibou57)
2013-05-15 9:28 ` Dmitry A. Kazakov
2013-05-15 11:31 ` Peter C. Chapin
2013-05-15 12:32 ` Yannick Duchêne (Hibou57)
2013-05-15 19:59 ` Peter C. Chapin
2013-05-15 20:56 ` Dmitry A. Kazakov
2013-05-15 12:46 ` Dmitry A. Kazakov
2013-05-15 18:15 ` Jeffrey Carter
2013-05-15 19:18 ` Eryndlia Mavourneen
2013-05-15 19:57 ` Dmitry A. Kazakov
2013-05-15 20:37 ` Yannick Duchêne (Hibou57)
2013-05-15 20:48 ` Dmitry A. Kazakov
2013-05-16 12:45 ` Eryndlia Mavourneen
2013-05-16 17:16 ` Jeffrey Carter
2013-05-16 9:41 ` G.B.
2013-05-16 12:35 ` J-P. Rosen
2013-05-15 14:21 ` J-P. Rosen
2013-05-14 2:14 ` Randy Brukardt
2013-05-14 19:35 ` Robert A Duff
2013-05-15 4:11 ` Yannick Duchêne (Hibou57)
2013-05-16 23:36 ` Randy Brukardt
2013-05-13 5:21 ` Niklas Holsti
2013-05-13 7:22 ` Dmitry A. Kazakov
2013-05-13 8:23 ` Yannick Duchêne (Hibou57)
2013-05-13 19:20 ` Niklas Holsti
2013-05-14 8:14 ` Dmitry A. Kazakov
2013-05-10 3:47 ` Yannick Duchêne (Hibou57)
2013-05-11 0:22 ` Randy Brukardt
2013-05-11 7:22 ` Yannick Duchêne (Hibou57)
2013-05-10 3:59 ` Yannick Duchêne (Hibou57)
2013-05-10 4:03 ` Yannick Duchêne (Hibou57)
2013-05-10 7:48 ` Dmitry A. Kazakov
2013-05-10 8:12 ` Yannick Duchêne (Hibou57)
2013-05-10 15:11 ` Yannick Duchêne (Hibou57)
2013-05-11 0:42 ` Randy Brukardt
2013-05-11 6:37 ` Dmitry A. Kazakov
2013-05-11 7:06 ` Georg Bauhaus
2013-05-11 7:42 ` Dmitry A. Kazakov
2013-05-11 8:14 ` Yannick Duchêne (Hibou57)
2013-05-14 2:29 ` Randy Brukardt
2013-05-14 7:44 ` Dmitry A. Kazakov
2013-05-14 11:34 ` Yannick Duchêne (Hibou57)
2013-05-14 12:16 ` Dmitry A. Kazakov
2013-05-14 13:13 ` Yannick Duchêne (Hibou57)
2013-05-14 18:41 ` Randy Brukardt
2013-05-15 11:20 ` Peter C. Chapin
2013-05-15 13:00 ` Dmitry A. Kazakov
2013-05-15 21:12 ` Peter C. Chapin
2013-05-15 22:08 ` Dmitry A. Kazakov
2013-05-16 11:31 ` Peter C. Chapin
2013-05-16 11:56 ` Yannick Duchêne (Hibou57)
2013-05-16 12:20 ` Dmitry A. Kazakov
2013-05-16 13:10 ` Peter C. Chapin
2013-05-16 13:54 ` Dmitry A. Kazakov [this message]
2013-05-16 17:15 ` G.B.
2013-05-16 18:09 ` Peter C. Chapin
2013-05-16 19:16 ` Dmitry A. Kazakov
2013-05-16 21:59 ` Georg Bauhaus
2013-05-17 19:57 ` Dmitry A. Kazakov
2013-05-16 21:20 ` Niklas Holsti
2013-05-16 23:20 ` Peter C. Chapin
2013-05-17 5:25 ` Niklas Holsti
2013-05-17 7:53 ` Georg Bauhaus
2013-05-16 13:09 ` Eryndlia Mavourneen
2013-05-11 7:58 ` Yannick Duchêne (Hibou57)
2013-05-11 9:08 ` Dmitry A. Kazakov
2013-05-11 18:14 ` Niklas Holsti
2013-05-11 8:03 ` Yannick Duchêne (Hibou57)
2013-05-11 9:16 ` Dmitry A. Kazakov
2013-05-11 11:49 ` Georg Bauhaus
2013-05-11 12:25 ` Dmitry A. Kazakov
2013-05-11 22:51 ` Robert A Duff
2013-05-12 6:02 ` Dmitry A. Kazakov
2013-05-12 6:25 ` Yannick Duchêne (Hibou57)
2013-05-12 7:14 ` Dmitry A. Kazakov
2013-05-12 7:37 ` Simon Wright
2013-05-12 7:59 ` Dmitry A. Kazakov
2013-05-12 8:21 ` Yannick Duchêne (Hibou57)
2013-05-12 9:25 ` Dmitry A. Kazakov
2013-05-12 9:32 ` Yannick Duchêne (Hibou57)
2013-05-12 10:07 ` Dmitry A. Kazakov
2013-05-11 7:32 ` Yannick Duchêne (Hibou57)
2013-05-11 7:46 ` Yannick Duchêne (Hibou57)
2013-05-14 12:46 ` Weaker typing as a part of the way to stronger typing? (Was: Seeking for papers about tagged types vs access to subprograms) Jacob Sparre Andersen
2013-05-14 19:08 ` Randy Brukardt
2013-05-10 16:02 ` Seeking for papers about tagged types vs access to subprograms Yannick Duchêne (Hibou57)
2013-05-08 20:12 ` Randy Brukardt
2013-05-09 7:50 ` Dmitry A. Kazakov
2013-05-09 21:43 ` Randy Brukardt
2013-05-10 4:39 ` Yannick Duchêne (Hibou57)
2013-05-10 7:49 ` Dmitry A. Kazakov
2013-05-11 0:09 ` Randy Brukardt
2013-05-11 6:40 ` Dmitry A. Kazakov
2013-05-14 3:01 ` Randy Brukardt
2013-05-14 8:32 ` Dmitry A. Kazakov
2013-05-14 19:02 ` Randy Brukardt
2013-05-15 4:43 ` Yannick Duchêne (Hibou57)
2013-05-16 23:27 ` Randy Brukardt
2013-05-15 9:14 ` G.B.
2013-05-15 12:08 ` Dmitry A. Kazakov
2013-05-15 14:43 ` G.B.
2013-05-15 15:02 ` Dmitry A. Kazakov
2013-05-14 19:21 ` Robert A Duff
2013-05-10 4:29 ` Yannick Duchêne (Hibou57)
2013-05-07 1:14 ` Randy Brukardt
2013-05-07 2:42 ` Yannick Duchêne (Hibou57)
2013-05-07 1:09 ` Randy Brukardt
2013-05-07 7:41 ` Dmitry A. Kazakov
2013-05-07 20:27 ` Jacob Sparre Andersen news
2013-05-07 20:40 ` Yannick Duchêne (Hibou57)
2013-05-08 7:57 ` Dmitry A. Kazakov
2013-05-08 20:37 ` Randy Brukardt
2013-05-09 8:04 ` Dmitry A. Kazakov
2013-05-09 21:33 ` Randy Brukardt
2013-05-10 7:15 ` Dmitry A. Kazakov
2013-05-11 1:00 ` Randy Brukardt
2013-05-11 7:08 ` Yannick Duchêne (Hibou57)
2013-05-11 7:12 ` Dmitry A. Kazakov
2013-05-14 2:52 ` Randy Brukardt
2013-05-11 5:31 ` Simon Wright
2013-05-11 7:22 ` Dmitry A. Kazakov
2013-05-02 1:09 ` Randy Brukardt
2013-05-02 6:56 ` Dmitry A. Kazakov
2013-05-02 21:49 ` Randy Brukardt
2013-05-03 6:49 ` Dmitry A. Kazakov
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox